Method for voltage monitoring of a power supply and circuit therefor

Abstract

The present application provides a voltage monitoring method and circuit for a power supply. A voltage dividing circuit is used to obtain a divided voltage of an input voltage of an input power supply of the power supply. A first detection circuit and a second detection circuit detect the input voltage according to the divided voltage. A threshold is used to determine whether to limit the divided voltage. The first detection circuit or the second detection circuit detects a detection current, and the other detection circuit detects the divided voltage. Thus, the input voltage transmitted from a rectifier circuit to the power supply is monitored, and the two detection circuits are independent of each other.

Description

Technical Field

[0001] This invention relates to a monitoring method and circuit thereof, particularly a method and circuit for monitoring the input voltage of a power supply. Background Technology

[0002] In existing AC-to-DC power supply devices, a high-voltage detection circuit and a low-voltage detection circuit are generally installed to detect the input voltage to the power supply device and provide different applications based on the detection results of the input voltage.

[0003] The aforementioned high-voltage and low-voltage detection circuits are typically integrated into a single integrated circuit chip. However, circuits integrated into a chip are practically difficult to adjust or modify. To facilitate changes to the high and low voltage detection thresholds, an external voltage divider circuit can be used to obtain a voltage division corresponding to the power supply's input voltage. Chip manufacturers can then reset the high and low voltage detection thresholds simply by changing the resistance ratio of the voltage divider circuit. However, to save on circuit costs, the high-voltage and low-voltage detection circuits can be designed to share a single voltage divider node. But this would cause the high and low voltage detection thresholds to become interdependent; that is, if the high-voltage detection threshold is adjusted by changing the voltage division ratio, the low-voltage detection threshold will also be affected, and vice versa.

[0004] Therefore, there is indeed a need to improve the existing technology. Summary of the Invention

[0005] One objective of this invention is to provide a voltage monitoring method and circuit for a power supply. The method involves obtaining a divided voltage of the input voltage of an input power source of the power supply using a voltage divider circuit, and determining whether a detection current is detected by a first detection circuit and the divided voltage is detected by a second detection circuit based on whether the divided voltage exceeds a threshold value. This method is used to monitor the input voltage transmitted to the power supply by a rectifier circuit and avoids the two detection circuits from becoming dependent on each other.

[0006] One objective of this invention is to provide a voltage monitoring method and circuit for a power supply. The method involves obtaining a divided voltage of the input voltage of an input power source of the power supply using a voltage divider circuit, and determining whether the second detection circuit should detect the detection current and the first detection circuit should detect the divided voltage based on whether the divided voltage exceeds a threshold value. This method is used to monitor the input voltage transmitted to the power supply by a rectifier circuit and avoids the two detection circuits from becoming dependent on each other.

[0007] To achieve the aforementioned objectives, the present invention provides a voltage monitoring method for a power supply, which is applied to monitor an input voltage of an input power source transmitted from a rectifier circuit to the power supply. The voltage monitoring method of the present invention involves first dividing the input voltage using a voltage divider circuit to obtain a divided voltage, and then using a first detection circuit and a second detection circuit to detect the input voltage based on the divided voltage. The first detection circuit and the second detection circuit respectively generate a first voltage signal and a second voltage signal based on the divided voltage, a first threshold value, and a second threshold value. The first detection circuit inhibits the divided voltage when the divided voltage exceeds a threshold value. The first detection circuit detects the input voltage of the power supply and the second detection circuit detects the input voltage based on the voltage divider. The first detection circuit generates a first voltage signal when it determines that the input voltage is greater than a first threshold value based on the current value of the detected current, and the second detection circuit generates a second voltage signal when it determines that the input voltage is less than a second threshold value based on the voltage value of the voltage divider. This monitors the input voltage of the power supply and avoids the first and second detection circuits from depending on each other, so that the component parameters of the first or second detection circuit can be adjusted independently.

[0008] The present invention also provides a voltage monitoring method for a power supply, which is applied to monitor an input voltage of an input power supply transmitted from a rectifier circuit to the power supply. The voltage monitoring method of the present invention first divides the input voltage using a voltage divider circuit to obtain a divided voltage, and then uses a first detection circuit and a second detection circuit to detect the input voltage based on the divided voltage. The first detection circuit and the second detection circuit respectively generate a first voltage signal and a second voltage signal based on the divided voltage, a first threshold value, and a second threshold value, wherein the second detection circuit inhibits the input voltage when the divided voltage exceeds a inhibition threshold value. The voltage divider detects a current value of a detection current flowing into the second detection circuit, and the first detection circuit detects the input voltage based on the voltage divider. The second detection circuit generates a second voltage signal when the current value of the detection current is less than the second threshold value, and the first detection circuit generates a first voltage signal when the voltage value of the voltage divider is greater than the first threshold value. This monitors the input voltage of the power supply and avoids the first detection circuit and the second detection circuit from depending on each other. Therefore, the component parameters of the first detection circuit or the second detection circuit can be adjusted independently.

[0009] The present invention further provides a voltage monitoring circuit for a power supply, which is used to monitor an input voltage of an input power supply transmitted from a rectifier circuit to the power supply. The voltage monitoring circuit of the present invention includes a first detection circuit and a second detection circuit. The first detection circuit and the second detection circuit are coupled between a first impedance element and a second impedance element of a voltage divider circuit, and obtain a divided voltage of the input power supply. When the divided voltage exceeds a threshold value, the first detection circuit inhibits the divided voltage. The first detection circuit determines the voltage based on the input voltage flowing into the first detection circuit. The first detection circuit detects the input voltage based on the current value of a detection current, and the second detection circuit detects the input voltage based on the voltage divider. When the first detection circuit determines that the input voltage is greater than the first threshold value based on the current value of the detection current, it generates a first voltage signal accordingly. When the second detection circuit determines that the input voltage is less than the second threshold value based on the voltage value of the voltage divider, it generates a second voltage signal accordingly. This is used to monitor the input voltage transmitted from a rectifier circuit to the power supply and to prevent the two detection circuits from becoming dependent on each other.

[0010] The present invention further provides a voltage monitoring circuit for a power supply, which is used to monitor an input voltage of an input power supply transmitted from a rectifier circuit to the power supply. The voltage monitoring circuit of the present invention includes a first detection circuit and a second detection circuit. The first detection circuit and the second detection circuit are coupled between a first impedance element and a second impedance element of a voltage divider circuit, and obtain a divided voltage of the input power supply. When the divided voltage exceeds a threshold value, the second detection circuit inhibits the divided voltage. The second detection circuit determines the voltage based on the input voltage. The first detection circuit detects the input voltage based on the current value of a detection current of the detection circuit. When the first detection circuit determines that the input voltage is greater than a first threshold value based on the voltage value of the voltage divider, it generates a first voltage signal accordingly. When the second detection circuit determines that the input voltage is less than a second threshold value based on the current value of the detection current, it generates a second voltage signal accordingly. This is used to monitor the input voltage transmitted from a rectifier circuit to the power supply and to prevent the two detection circuits from depending on each other. Attached Figure Description

[0011] Figure 1 This is a schematic flowchart of a voltage monitoring method for a power supply according to an embodiment of the present invention.

[0012] Figure 2 This is a circuit diagram of the first embodiment of the present invention;

[0013] Figure 3 This is a schematic diagram of the signal at the output terminal of the voltage acquisition unit in the first embodiment of the present invention;

[0014] Figure 4 This is a schematic diagram of the input voltage signal from the power supply to the power supply of the present invention;

[0015] Figure 5 This is a schematic diagram of the signal in which the voltage divider voltage of the present invention is suppressed;

[0016] Figure 6 This is a schematic diagram illustrating a detailed circuit example of the detection circuit according to the first embodiment of the present invention.

[0017] Figure 7 This is a circuit diagram of the second embodiment of the present invention;

[0018] Figure 8 This is a schematic flowchart of a voltage monitoring method for a power supply according to another embodiment of the present invention.

[0019] Figure 9 This is a circuit diagram of the third embodiment of the present invention;

[0020] Figure 10 This is a schematic diagram of the signal at the output terminal of the rectifier circuit according to the third embodiment of the present invention; and

[0021] Figure 11 This is a circuit diagram of the fourth embodiment of the present invention.

[0022] [Figure Number Reference Guide]

[0023] 10 Power supply unit

[0024] 12 Voltage Acquisition Units

[0025] 122 First Diode

[0026] 124 Second Diode

[0027] 14 Rectifier Circuit

[0028] 16 Voltage Monitoring Circuit

[0029] 162 First Detection Circuit

[0030] 1622 Current Mirror

[0031] 1624 Reference Current Source

[0032] 1626 First Signal Processing Unit

[0033] 164 Second Detection Circuit

[0034] 1642 comparator

[0035] 1644 Second Signal Processing Unit

[0036] 18 Power Supply

[0037] AC power supply

[0038] C Input capacitor

[0039] D1 First rectifier element

[0040] D2 Second rectifier element

[0041] D3 Third rectifier element

[0042] D4 Fourth rectifier element

[0043] DIV voltage divider circuit

[0044] I IN1 restraining current

[0045] I IN2 restraining current

[0046] I OUT1 First mirror current

[0047] I OUT2 Second mirror current

[0048] I REF1 First reference current

[0049] I REF2 Second reference current

[0050] M11 First Input Transistor

[0051] M12 First mirror transistor

[0052] M13 First Output Transistor

[0053] M1 IN First mirror input unit

[0054] M1 OUT First Image Output Unit

[0055] M2 IN Second mirror input unit

[0056] M2 OUT Second mirror output unit

[0057] OUT Comparison Results

[0058] OP operational amplifier

[0059] SW switching element

[0060] V IN Input voltage

[0061] VDIV partial pressure

[0062] V REF1 Reference voltage

[0063] V REF2 Reference voltage

[0064] VT1 First Voltage Signal

[0065] VT2 Second Voltage Signal

[0066] Z U First impedance element

[0067] Z D Second impedance element. Detailed Implementation

[0068] To provide a better understanding of the structural features and effects achieved by the present invention, preferred embodiments and detailed descriptions are provided below:

[0069] To address the problem of threshold dependence in the two detection circuits of the prior art, this invention proposes a voltage monitoring circuit and method for a power supply. The circuit uses a detection circuit to control the voltage division of an input power supply when the voltage division exceeds or does not exceed a control threshold and to detect a detection current flowing into it. Another detection circuit is responsible for detecting the voltage division, thus avoiding dependence between the two detection circuits.

[0070] The invention will be described in detail below by way of the drawings illustrating various embodiments thereof. However, the concept of the invention may be embodied in many different forms and should not be construed as being limited to the exemplary embodiments set forth herein.

[0071] Please see Figure 1 This is a schematic flowchart illustrating the voltage monitoring method of the power supply in various embodiments of the present invention. To facilitate the explanation of the voltage monitoring methods in each embodiment, the relevant circuits used in the voltage monitoring methods of each embodiment will be described below.

[0072] First, please refer to Figure 2 This is a circuit diagram of a first embodiment of the present invention. As shown in the figure, a power supply device 10 of this embodiment receives an AC power supply and includes a voltage extraction unit 12, a rectifier circuit 14, a voltage monitoring circuit 16, and a power supply unit 18. The voltage extraction unit 12 includes a first diode 122 and a second diode 124 to convert the AC power supply into a DC extraction voltage V. DThe rectifier circuit 14 is typically a bridge rectifier circuit, comprising a first rectifier element D1, a second rectifier element D2, a third rectifier element D3, and a fourth rectifier element D4, to rectify the AC power supply to form a DC input power supply and provide it to the power supply 18. However, the present invention is not limited thereto. The voltage monitoring circuit 16 comprises a first detection circuit 162 and a second detection circuit 164, which are coupled to a voltage divider circuit DIV. The voltage divider circuit DIV includes a first impedance element Z coupled to each other. U With a second impedance element Z D The first impedance element Z U With the second impedance element Z D There is a voltage divider V between them. DIV In this embodiment, the voltage acquisition unit 12 provides the acquired voltage V based on the AC power supply AC. D This leads to the voltage divider circuit DIV, thus allowing the voltage divider circuit DIV to pass through the first impedance element Z. U With the second impedance element Z D Provide this voltage divider V DIV Among them, the sampling voltage V D It is an input voltage V related to the input power supply from the rectifier circuit 14 to the power supply 18. IN Therefore, the voltage monitoring circuit 16 can detect the voltage drop across the voltage divider V. DIV To monitor the input voltage V IN .

[0073] For more details, please refer to [link / reference]. Figure 3 The voltage extraction unit 12 in this embodiment converts the AC power supply AC into a DC extraction voltage V. D The waveform diagram afterward. Figure 4 The rectifier circuit 14 generates a rectified DC input power supply based on the AC power supply. The rectifier circuit 14 utilizes the first rectifier element D1, the second rectifier element D2, the third rectifier element D3, and the fourth rectifier element D4 as diodes and an input capacitor C to store energy, resulting in an input voltage V of the generated input power supply. IN Figure 4 The waveform shown is output to the power supply 18. As can be seen from Figures 3 and 4, the extracted voltage V... D It relates to the input voltage V of the rectifier circuit 14 to the power supply 18. IN Therefore, it can be used to monitor the input voltage V. IN .

[0074] In the voltage monitoring circuit 16 of this embodiment, the first detection circuit 162 and the second detection circuit 164 are based on the voltage divider voltage VDIV Detect the input voltage V IN Therefore, the first detection circuit 162 and the second detection circuit 164 respectively rely on the voltage divider V DIV A first threshold value Vth1 and a second threshold value Vth2 generate a first voltage signal VT1 or a second voltage signal VT2, wherein, in this embodiment, the first threshold value Vth1 corresponds to a first reference current I of the first detection circuit 162. REF1 The second threshold value Vth2 corresponds to a reference voltage V of the second detection circuit 164. REF1 The first reference current I REF1 With the reference voltage V REF1 These are the default parameter values ​​for the first detection circuit 162 and the second detection circuit 164 during IC circuit design and manufacturing. The first detection circuit 162 and the second detection circuit 164 can include analog circuits and logic operation circuits.

[0075] In detail, in this embodiment, when the voltage divider V DIV Exceeding the one-stroke threshold value VC (e.g.) Figure 5 When (as shown), the first detection circuit 162 controls the voltage divider V. DIV This makes the voltage V of the voltage divider... DIV Maintaining the value equal to or close to the restraint threshold VC, and based on a detection current I flowing into the first detection circuit 162. IN1 The current value is detected by the input voltage V. IN Among them, because of the voltage V DIV The voltage V is restrained when the AC power supply voltage increases, causing the extracted voltage V to... D Increase the detection current I flowing into the first detection circuit 162 IN1 The voltage V will increase with the increase of the AC power supply; conversely, when the AC power supply voltage decreases, the extracted voltage V will decrease. D The detection current I flowing into the first detection circuit 162 is reduced. IN1 The detection current I will decrease accordingly; therefore, the detection current I IN1 It can be used to determine the AC power supply (AC) and the input voltage (V). IN The magnitude of the input voltage V. Therefore, when the first detection circuit 162 determines the input voltage V based on the current value of the detected current. IN When the voltage exceeds the first threshold value Vth1, the first detection circuit 162 generates the first voltage signal VT1.

[0076] Once the sampling voltage V D Reduce to the point that the voltage V is reduced DIV If the voltage threshold VC is not exceeded, the first detection circuit 162 will stop controlling the voltage divider V. DIVThe second detection circuit 164 is based on the voltage divider V. DIV Detect the input voltage V IN When the second detection circuit 164 detects the voltage V, DIV The voltage value determines the input voltage V. IN When the voltage is less than the second threshold value Vth2, the second detection circuit 164 generates the second voltage signal VT2.

[0077] More specifically, in this embodiment, the first detection circuit 162 includes a current mirror 1622, a reference current source 1624, and a first signal processing unit 1626, and the current mirror 1622 includes a first mirror input unit M1. IN With a first mirror output unit M1 OUT via the first mirror input terminal M1 IN At this voltage divider V DIV When the voltage exceeds the threshold value VC, the voltage divider voltage V is restricted. DIV and receive a detection current I IN1 To the first mirror input unit M1 IN And the first mirror output unit M1 OUT Corresponding output: First mirror current I OUT1 In this embodiment, the reference current source 1624 provides the first reference current I. REF1 The first signal processing unit 1626 processes signals based on the first reference current I. REF1 With the first mirror current I OUT1 The current value determines the detected current I. IN1 The magnitude of the input voltage V is used to determine the value of the input voltage V. IN Whether it exceeds the first threshold value Vth1, and in determining the input voltage V IN When the voltage exceeds the first threshold value Vth1, the first voltage signal VT1 is generated. The detected current I... IN1 The input current of the current mirror 1622, the first mirror current I OUT1 This is an output current of the current mirror 1622, and the two are in a multiple relationship; in other words, the detected current I... N1 With the first mirror current I OUT1 The ratio is K, that is, I. N1 :I OUT1 = 1:K, which can be adjusted according to usage requirements. This threshold value VC is greater than a reference voltage V used by the second detection circuit 164. REF1 (Details are as follows), and when the voltage divider V DIV When the current I is less than the control threshold value VC, the detection current I IN1 Ideally, the current value should be 0.

[0078] In this embodiment, the second detection circuit 164 includes a comparator 1642 and a second signal processing unit 1644. The comparator 1642 includes a positive input terminal and a negative input terminal. The comparator 1642 is coupled to the reference voltage V through the positive input terminal. REF1 And the voltage divider V is coupled through the negative input terminal. DIV Therefore, the comparator 1642 generates a comparison result OUT through an output terminal and sends it to the second signal processing unit 1644, so that the second signal processing unit 1644 can determine the input voltage V based on the comparison result OUT. IN Whether it is less than the second threshold value Vth2, and in determining the input voltage V IN When the voltage is less than the second threshold value Vth2, the second voltage signal VT2 is generated.

[0079] Furthermore, in this embodiment, the power supply 18 executes a first operating mechanism based on the first voltage signal VT1, for example: the first operating mechanism may be an overvoltage protection, a high voltage judgment, or an input voltage switching; the power supply 18 executes a second operating mechanism based on the second voltage signal VT2, for example: the second operating mechanism may be an undervoltage protection or a minimum start-up voltage setting.

[0080] As described above, the voltage monitoring circuit 16 of the present invention utilizes the first detection circuit 162 and the second detection circuit 164 based on the voltage divider voltage V. DIV Detect the input voltage V IN Therefore, the first detection circuit 162 and the second detection circuit 164 respectively rely on the voltage divider V DIV The first threshold value Vth1 and the second threshold value Vth2 generate the first voltage signal VT1 or the second voltage signal VT2. Simultaneously, when the voltage divider V... DIV Exceeding the threshold value VC (e.g.) Figure 5 When (as shown), the first detection circuit 162 controls the voltage divider V. DIV And based on the detected current I IN1 The current value is detected by the input voltage V. IN The second detection circuit 164 is based on the voltage divider V. DIV Detect the input voltage V IN Therefore, the first detection circuit 162 and the second detection circuit 164 can be used to detect the input voltage V. IN Furthermore, the parameters of the first detection circuit 162 and the second detection circuit 164 can be set separately.

[0081] Continuing from the above, such as Figure 6The diagram shows a detailed circuit example of constructing the first detection circuit 162, including the first mirror input unit M1. IN It includes an operational amplifier OP, an input transistor M11, and a first mirror transistor M12, wherein the first mirror output unit M1 OUT The operational amplifier OP includes a first output transistor M13, which is coupled to the threshold value VC via a positive input terminal of the operational amplifier OP, and the voltage divider voltage V is coupled to a negative input terminal of the operational amplifier OP. DIV Therefore, at this voltage divider V DIV When the threshold value VC is not exceeded, the input transistor M11 is turned off, causing the first detection circuit 162 to be inactive. At this time, the first detection circuit 162 does not affect the voltage divider V. DIV Once the voltage divider V DIV When the threshold value VC is exceeded, the operational amplifier OP controls the input transistor M11 to turn on the detection current I. IN1 The virtual short-circuit characteristic of the operational amplifier (OP) is used to control the voltage divider V. DIV To maintain it at or near the restraint threshold value VC, and to generate the first mirror current I using the current mirror formed by the first mirror transistor M12 and the first output transistor M13. OUT1 The first signal processing unit 1626 then uses the first reference current I... REF1 With the first mirror current I OUT1 The first voltage signal VT1 is generated.

[0082] As described above, in the voltage monitoring method and circuit of the power supply in the first embodiment of the present invention, the first threshold value Vth1 and the second threshold value Vth2 can be expressed as follows:

[0083]

[0084] The following is a simple numerical example. Suppose that the first threshold value Vth1 and the second threshold value Vth2 are to be set to 300VAC and 80VAC respectively, and the first reference current I... REF1 The current is selected as 50μA, the restraint threshold VC is selected as 1V, and the second reference voltage V... REF1 The selected value is 0.8V, and the detection current I... N1 With the first mirror current I OUT1 The ratio K is chosen to be 1; these are usually the default parameter values ​​used in IC circuit design and manufacturing. However, the first impedance element Z... U With the second impedance element Z D Generally, these are components coupled externally to the IC. Therefore, the first impedance element Z can be calculated using the above formula under the aforementioned selected preset parameter values. UWith the second impedance element Z D The impedance values ​​are 5.656 megaohms (MΩ) and 40.2849 kiloohms (kΩ), respectively, and the first threshold value Vth1 and the second threshold value Vth2 can be correctly set to 300VAC and 80VAC, respectively.

[0085] Furthermore, assuming the first threshold value Vth1 is desired to be adjusted to 250VAC, but the second threshold value Vth2 is still desired to be maintained at 80VAC, and assuming the aforementioned selected preset parameter values ​​remain unchanged, the first impedance element Z can be calculated using the above formula. U With the second impedance element Z D The impedance values ​​are 4.1311 megaohms (MΩ) and 29.4194 kiloohms (kΩ), respectively, which can adjust the first threshold value Vth1 to 250VAC without affecting the second threshold value Vth2.

[0086] Therefore, although the embodiments of the present invention also use only one voltage divider node to monitor the input voltage, the first impedance element Z can be changed. U With the second impedance element Z D The impedance value is used to independently set and adjust the first threshold value Vth1 and the second threshold value Vth2, and the first threshold value Vth1 and the second threshold value Vth2 are not dependent on each other. In this embodiment, the first impedance element Z U With the second impedance element Z D The impedance value is illustrated using resistance as an example, but it is not limited to this. Other components such as capacitors or inductors can also be used to construct the first impedance element Z. U With the second impedance element Z D In other words, the present invention can further utilize the first reference current I. REF1 The reference voltage V REF1 The first impedance element Z U A first impedance value and the second impedance element Z D The first threshold value Vth1 and the second threshold value Vth2 are set or adjusted together by a second impedance value.

[0087] like Figure 7 The diagram shown is a circuit schematic of the second embodiment of the present invention. Wherein, Figure 2 and Figure 7 The difference lies in Figure 2 The voltage monitoring circuit 16 is coupled to a voltage acquisition unit 12, that is, coupled between the AC power supply AC and the rectifier circuit 14. Figure 7The voltage monitoring circuit 16 is coupled between the rectifier circuit 14 and the power supply 18. Since the voltage divider circuit DIV in this embodiment directly relies on the input voltage V... IN This divider voltage V is generated DIV Therefore, the voltage V in this embodiment is... DIV To be directly related to the input voltage V IN Furthermore, the power supply device 10A in this embodiment does not include the voltage acquisition unit 12.

[0088] In this embodiment, besides receiving the rectified input voltage V, IN To generate this voltage divider V DIV Unlike the first embodiment of the present invention, the remaining signal operations are largely the same as those in the first embodiment, and therefore will not be described again.

[0089] The above embodiment describes the first detection circuit 162 based on the detected current I. N1 Detect the input voltage V IN Whether it is greater than the first threshold value Vth1, and the second detection circuit 164 based on the voltage divider V DIV Detect the input voltage V IN Whether it is less than the second threshold value Vth2, but the present invention is not limited to this, and the two can be interchanged. Please refer to [reference needed]. Figure 8 This is a schematic flowchart of a voltage monitoring method for a power supply according to another embodiment of the present invention, and the relevant circuits used are described in detail below:

[0090] like Figure 9 The diagram shown is a circuit schematic of the third embodiment of the present invention. In the foregoing embodiments, the first detection circuit 162 can be connected via the first mirror input unit M1. IN An input transistor M11 is used to determine the voltage divider voltage V. DIV The magnitude of the current I can be actively turned on or off by the first detection circuit 162. However, in this embodiment, the first detection circuit 162 may further include a switching element SW, which can be controlled by the first signal processing unit VT1 to determine whether to turn on a detection current I. IN2 On the other hand, the current mirror 1622 in this embodiment includes a second mirror input unit M2. IN With a second mirror output unit M2 OUT Furthermore, in this embodiment, the reference current source 1624 provides a second reference current I. REF2 When the voltage divider V DIV When the threshold value VC is not exceeded, the switching element SW is turned on and the voltage divider V is restrained. DIV Therefore, a detection current I is turned on. IN2The second current mirror 1646 includes a first mirror input unit M2. IN With a second mirror output unit M2 OUT The first mirror input unit M2 IN Receive the detected current I IN2 Similarly, the second mirror output unit M2 OUT Generate a corresponding second mirror current I OUT2 The first signal processing unit 1626 is based on the second reference current I REF2 and the second mirror current I OUT2 Determine the input voltage V IN Whether it is less than the first threshold value Vth1, when the first signal processing unit 1626 determines the input voltage V IN The first voltage signal VT1 is generated when the voltage is less than the first threshold value Vth1. Figure 10 As shown, the first threshold value Vth1 in this embodiment is a relatively low threshold value.

[0091] Once the sampling voltage V D Increase until the voltage V of the voltage divider is reached DIV If the voltage exceeds the limiting threshold VC, the switching element S will turn off, and therefore the first detection circuit 162 will stop limiting the voltage divider V. DIV The second detection circuit 164 in this embodiment receives the divided voltage V. DIV The comparator 1642 uses a reference voltage V to... REF2 With the voltage divider V DIV The comparison result OUT is generated and sent to the second signal processing unit 1644, so that the second signal processing unit 1644 can determine the input voltage V based on the comparison result OUT. IN Whether it is greater than the second threshold value Vth2, and in determining the input voltage V IN When the voltage is greater than the second threshold value Vth2, the second signal processing unit 1644 generates the second voltage signal VT2. In this embodiment, the second threshold value Vth2 is greater than the first threshold value Vth1; therefore, this embodiment is equivalent to using the first detection circuit 162 to detect the input voltage V based on the lower voltage threshold Vth1. IN The second detection circuit 164 detects the input voltage V based on a higher voltage threshold Vth2. IN .

[0092] like Figure 11 The diagram shown is a circuit schematic of the fourth embodiment of the present invention. In this embodiment, the voltage divider circuit DIV is instead coupled between the rectifier circuit 14 and the power supply 18. The remaining connections are the same as in the previous embodiment, and therefore will not be described again.

[0093] Similarly, in the third and fourth embodiments of the present invention, when the voltage monitoring circuit 16 sets or adjusts the first threshold value Vth1 or the second threshold value Vth2, it can change the first impedance element Z. U With the second impedance element Z D The impedance value is used to independently set and adjust the first threshold value Vth1 or the second threshold value Vth2, and the first threshold value Vth1 and the second threshold value Vth2 are not dependent on each other. In this embodiment, the first impedance element Z U With the second impedance element Z D The impedance value is illustrated using resistance as an example, but it is not limited to this. Other components such as capacitors or inductors can also be used to construct the first impedance element Z. U With the second impedance element Z D In other words, the present invention can further utilize this reference voltage V. REF2 The second reference current I REF2 The first impedance element Z U A first impedance value and the second impedance element Z D The first threshold value Vth1 and the second threshold value Vth2 are set or adjusted together by a second impedance value.

[0094] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent variations and modifications made in accordance with the shape, structure, features and spirit described in the claims of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A voltage monitoring method for a power supply, characterized in that, It is used to monitor an input voltage of an input power supply transmitted from a rectifier circuit to the power supply, and the voltage monitoring method of the power supply includes: A voltage divider circuit is used to obtain a divided voltage from the input power supply. This voltage divider circuit includes a first impedance element and a second impedance element. A first detection circuit and a second detection circuit detect the input voltage based on the divided voltage of the input power supply. The first detection circuit and the second detection circuit generate a first voltage signal or a second voltage signal based on the voltage divider, a first threshold value and a second threshold value; Specifically, when the voltage divider exceeds a threshold value, the first detection circuit limits the voltage divider and detects the input voltage based on the current value of a detection current flowing into the first detection circuit; the second detection circuit detects the input voltage based on the voltage divider; when the first detection circuit determines that the input voltage is greater than the first threshold value based on the current value of the detection current, the first detection circuit generates the first voltage signal; when the second detection circuit determines that the input voltage is less than the second threshold value based on the voltage value of the voltage divider, the second detection circuit generates the second voltage signal.

2. The voltage monitoring method for a power supply as described in claim 1, characterized in that, in, The first detection circuit determines whether the input voltage is greater than the first threshold value based on a reference current and the detection current, and the second detection circuit determines whether the input voltage is less than the second threshold value based on a reference voltage and the voltage divider voltage.

3. The voltage monitoring method for a power supply as described in claim 2, characterized in that, The reference current, the reference voltage, a first impedance value of the first impedance element, and a second impedance value of the second impedance element are used to set or adjust the first threshold value and the second threshold value.

4. The voltage monitoring method for a power supply as described in claim 3, characterized in that, It also includes changing the first impedance value and the second impedance value to independently set or adjust the first threshold value and the second threshold value.

5. The voltage monitoring method for a power supply as described in claim 1, characterized in that, The power supply executes a first operating mechanism based on the first voltage signal, and executes a second operating mechanism based on the second voltage signal.

6. The voltage monitoring method for a power supply as described in claim 5, characterized in that, The first actuation mechanism is an overvoltage protection, a high voltage judgment, or an input voltage switching mechanism, and the second actuation mechanism is an undervoltage protection or a minimum start-up voltage setting mechanism.

7. A voltage monitoring method for a power supply, characterized in that, It is used to monitor an input voltage of an input power supply transmitted from a rectifier circuit to the power supply, and the voltage monitoring method of the power supply includes: A voltage divider circuit is used to obtain a divided voltage from the input power supply. This voltage divider circuit includes a first impedance element and a second impedance element. A first detection circuit and a second detection circuit detect the input voltage based on the divided voltage of the input power supply. The first detection circuit and the second detection circuit generate a first voltage signal or a second voltage signal based on the input voltage, a first threshold value and a second threshold value; Specifically, when the voltage divider does not exceed a threshold value, the first detection circuit controls the voltage divider and detects the input voltage based on the current value of a detection current flowing into the first detection circuit; the second detection circuit detects the input voltage based on the voltage divider; when the first detection circuit determines that the input voltage is less than the first threshold value based on the current value of the detection current, the first detection circuit generates the first voltage signal; when the second detection circuit determines that the input voltage is greater than the second threshold value based on the voltage value of the voltage divider, the second detection circuit generates the second voltage signal.

8. The voltage monitoring method for a power supply as described in claim 7, characterized in that, in, The first detection circuit determines whether the input voltage is less than the first threshold value based on a reference current and the detection current, and the second detection circuit determines whether the input voltage is greater than the second threshold value based on a reference voltage and the voltage divider voltage.

9. The voltage monitoring method for a power supply as described in claim 8, characterized in that, The reference current, the reference voltage, a first impedance value of the first impedance element, and a second impedance value of the second impedance element are used to set or adjust the first threshold value and the second threshold value.

10. The voltage monitoring method for a power supply as described in claim 7, characterized in that, It further includes changing a first impedance value of the first impedance element and a second impedance value of the second impedance element to independently set or adjust the first threshold value and the second threshold value.

11. The voltage monitoring method for a power supply as described in claim 7, characterized in that, The power supply executes a first operating mechanism based on the first voltage signal, and executes a second operating mechanism based on the second voltage signal.

12. The voltage monitoring method for a power supply as described in claim 11, characterized in that, The first actuation mechanism is an overvoltage protection, a high voltage judgment, or an input voltage switching mechanism, and the second actuation mechanism is an undervoltage protection or a minimum start-up voltage setting mechanism.

13. A voltage monitoring circuit for a power supply, characterized in that, It is used to monitor an input voltage of an input power supply transmitted from a rectifier circuit to the power supply, the voltage monitoring circuit of the power supply comprising: A first detection circuit is coupled between a first impedance element and a second impedance element of a voltage divider circuit to obtain a divided voltage of the input power supply. When the divided voltage exceeds a threshold value, the first detection circuit suppresses the divided voltage. The first detection circuit detects the input voltage based on the current value of a detection current flowing into the first detection circuit. A second detection circuit is coupled between the first impedance element and the second impedance element to obtain the voltage divider voltage, and the second detection circuit detects the input voltage based on the voltage divider voltage; Specifically, when the first detection circuit determines that the input voltage is greater than a first threshold value based on the current value of the detected current, the first detection circuit generates a first voltage signal; when the second detection circuit determines that the input voltage is less than a second threshold value based on the voltage value of the voltage divider, the second detection circuit generates a second voltage signal.

14. The voltage monitoring circuit of the power supply as described in claim 13, characterized in that, The first detection circuit determines whether the input voltage is greater than the first threshold value based on a reference current and the detection current, and the second detection circuit determines whether the input voltage is less than the second threshold value based on a reference voltage and the voltage divider voltage.

15. The voltage monitoring circuit of the power supply as described in claim 14, characterized in that, The reference current, the reference voltage, a first impedance value of the first impedance element, and a second impedance value of the second impedance element are used to set or adjust the first threshold value and the second threshold value.

16. The voltage monitoring circuit of the power supply as described in claim 13, characterized in that, The first detection circuit includes a current mirror, the detection current is an input current of the current mirror, the detection current is a multiple of an output current of the current mirror, and the output current is compared with a reference current to determine whether the input voltage is greater than the first threshold value.

17. The voltage monitoring circuit of the power supply as described in claim 16, characterized in that, The first detection circuit further includes a switch, which is coupled between the first impedance element and the second impedance element and the current mirror. When the voltage divider exceeds the restraint threshold, the first detection circuit turns on the switch to restrain the voltage divider, so that the voltage divider is maintained at or close to the restraint threshold, and generates a detection current flowing into the current mirror.

18. A voltage monitoring circuit for a power supply, characterized in that, It is used to monitor an input voltage of an input power supply transmitted from a rectifier circuit to the power supply, the voltage monitoring circuit of the power supply comprising: A first detection circuit is coupled between a first impedance element and a second impedance element of a voltage divider circuit to obtain a divided voltage of the input power supply. When the divided voltage does not exceed a threshold value, the first detection circuit limits the divided voltage. The first detection circuit detects the input voltage based on the current value of a detection current flowing into the first detection circuit. A second detection circuit is coupled between the first impedance element and the second impedance element to obtain the voltage divider voltage. The second detection circuit detects the input voltage based on the voltage divider voltage. Specifically, when the first detection circuit determines that the input voltage is less than a first threshold value based on the current value of the detected current, the first detection circuit generates a first voltage signal; when the second detection circuit determines that the input voltage is greater than a second threshold value based on the voltage value of the voltage divider, the second detection circuit generates a second voltage signal.

19. The voltage monitoring circuit of the power supply as described in claim 18, characterized in that, The first detection circuit determines whether the input voltage is less than the first threshold value based on a reference current and the detection current, and the second detection circuit determines whether the input voltage is greater than the second threshold value based on a reference voltage and the voltage divider voltage.

20. The voltage monitoring circuit of the power supply as described in claim 19, characterized in that, The reference current, the reference voltage, a first impedance value of the first impedance element, and a second impedance value of the second impedance element are used to set or adjust the first threshold value and the second threshold value.

21. The voltage monitoring circuit of the power supply as described in claim 18, characterized in that, The first detection circuit includes a current mirror, the detection current is an input current of the current mirror, the detection current is a multiple of an output current of the current mirror, and the output current is compared with a reference current to determine whether the input voltage is less than the first threshold value.

22. The voltage monitoring circuit of the power supply as described in claim 21, characterized in that, The first detection circuit further includes a switch, which is coupled between the first impedance element and the second impedance element and the current mirror. When the voltage divider does not exceed the restraint threshold value, the first detection circuit turns on the switch to restrain the voltage divider, so that the voltage divider is maintained at or close to the restraint threshold value, and generates a detection current flowing into the current mirror.

Images